THERMAL NEUTRON DETECTION

EJ-426

EJ-426 is an efficient detector for thermal neutrons with low sensitivity to gamma radiation. The detector has the form of a flat, white, thin sheet consisting of a homogeneous matrix of fine particles of lithium-6-fluoride (6LiF) and zinc sulfide phosphor (ZnS:Ag) compactly dispersed in a colorless binder. The lithium is enriched in 6Li to a minimum of 95 atom %.

with a cross section of 941 barns for 0.025 eV neutrons. The resulting triton and alpha particle are detected by ZnS:Ag phosphor with the broad blue fluorescent spectrum shown below. The decay time of the prompt scintillation component is 200 ns.

EJ-426 sheets can be manufactured in a large variety of sizes and formulas and are usually supplied with a support backing. Most types are heat formable. The tables below present the product variations currently available.